On Mon, Jul 30, 2018 at 09:10:52AM +0000, Bean Huo (beanhuo) wrote: > Hi, ext4 experts > For some cases, the storage device inside(FW) already has readahead feature. > I want to disable ext4 readahead and do some test. And see what is the difference > between these situations. > But I tried "inode_readahead_blks" parameter to disable readahead, but it doesn't work. > What else I need to set for disabling ext4 readahead? inode_readahead_blks, as it is documented, only controls readahead of inode table blocks. If you want to control the data readahead, that's a general setting that applies for all file systems, and it can be found by adjusting the value in: /sys/block/<dev>/queue/read_ahead_kb (where <dev> might be sda, sdb, etc.) See https://cromwell-intl.com/open-source/performance-tuning/disks.html for more details. - Ted
